Index Medicus
Index Medicus (IM) was a comprehensive bibliographic index of life science, biomedical science, and medical research articles, published from 1879 to 2004. Medical history experts have said of Index Medicus that it is “America's greatest contribution to medical knowledge.” It was published as a print index until 2004; beginning in the 1960s, it was also published as an electronic database, MEDLARS. Index Medicus content from 1940s to 2004 was incorporated into MEDLINE and PubMed; older medical literature, however, is not electronically available.